Novel benzonitriles, benzaldehydes and benzyl alcohols

ABSTRACT

Novel benzonitriles, benzaldehydes and benzyl alcohols of the formula I ##STR1## where R 1  is methyl or ethyl, R 2  is alkyl, alkenyl, cycloalkyl, cycloalkenyl, bicycloalkyl, bicycloalkenyl, or C 1  -C 5  -alkyl-substituted cycloalkyl, cycloalkenyl, bicycloalkyl or bicycloalkenyl, X is hydrogen, chlorine or fluorine and Z is --CN, CHO or ##STR2## where R 3  is hydrogen, cyano, C 2  -C 4  -alkynyl, C 2  -C 4  -alkenyl or C 1  -C 4  -alkyl, with the proviso that R 2  is not --CH 2  -CH═CH--B when B is hydrogen, alkyl or alkenyl and at the same time R 1  is methyl and Z is ##STR3## and with the proviso that R 2  is not methyl or ethyl when R 1  is methyl and at the same time Z is ##STR4## and further more with the proviso that R 2  is not methyl when R 1  is methyl or ethyl and at the same time Z is --CN or --CHO.

This is a division of application Ser. No. 07/365,794, filed on June 14,1989, now U.S. Pat. No. 4,950,796, issued Aug. 21, 1990.

The present invention relates to novel benzonitriles, benzaldehydes andbenzyl alcohols of the general formula I ##STR5## where R¹ is methyl orethyl, R² is alkyl, alkenyl, cycloalkyl, cycloalkenyl, bicycloalkyl,bicycloalkenyl or C₁ -C₅ -alkyl-substituted cycloalkyl, cycloalkenyl,bicycloalkyl or bicycloalkenyl, X is hydrogen, chlorine or fluorine andZ is --CN, CHO or ##STR6## where R³ is hydrogen, cyano, C₂ -C₄ -alkynyl,C₂ -C₄ -alkenyl or C₁ -C₄ -alkyl, with the proviso that R² is not --CH₂--CH═CH--B when B is hydrogen, alkyl or alkenyl and at the same time R¹is methyl and Z is ##STR7## and with the proviso that R² is not methylor ethyl when R¹ is methyl and at the same time Z is ##STR8## andfurthermore with the proviso that R² is not methyl when R¹ is methyl orethyl and at the same time Z is --CN or --CHO.

2,3-Dimethylbenzyl alcohol, 3-ethyl-2-methylbenzyl alcohol and2,3-dimethyl-α-methylbenzyl alcohol are described in, for example, J.Chem. Soc., Perkin Trans. 1 (12) (1981), 3087-3091; J. Chem. Soc.,Perkin Trans. 1 (20) (1974), 2339-2342; Helv. Chim. Acta, 60 (5)1758-1780 and Tetrahedron Lett. 22 (1981), 161-162.

Furthermore, Pestic. Sci. 17 (6) (1986), 691-700 discloses certainortho-methylbenzyl alcohols which carry in the meta-position an allylradical which may be substituted at the terminal position.

2,3-Dimethylbenzaldehyde and 2-ethyl-3-methylbenzaldehyde are describedin J. Chem. Soc., Perkin Trans. 1 (1981), 3087-3091, J. Org. Chem. 47(1982), 1361-1364 and Indian J. Chem. Sect. B, 258 (1986), 1112-1117.

2,3-Dimethylbenzonitrile, 2-ethyl-3-methylbenzonitrile and4-chloro-2,3-dimethylbenzonitrile are disclosed in J. Chem. Soc., PerkinTrans. 2 (1983), 1003-1010, Indian J. Chem. Sect. B, 25B (1986),1112-1117 and J. Chem. Soc., 1964, 2258-2261.

It is an object of the present invention to provide novel intermediatesfor the preparation of pesticides, in particular of benzyl esters of thestructure IV ##STR9## where A is a carboxylate radical of an acidcomponent typical for pyrethroids and R¹ to R³ and X have theabove-mentioned meanings.

We have found that this object is achieved and that the compoundsdefined at the outset are particularly suitable for the preparation ofbenzyl esters IV which have good insecticidal and acaricidal activityand are described in contemporaneous German Application P 38 20 896.2.

The benzyl esters of the formula IV can be obtained by reacting an acidA--H, some typical examples of which are listed below, or a derivativeof this acid, such as an acyl chloride, an anhydride or the like, with abenzyl alcohol of the general formula Ia or a derivative thereof inaccordance with the equation below. ##STR10## R¹ to R³ and X have theabovementioned meanings. Typical examples of the acids of the formulaA--H are:

A¹ --H: 3-(2',2'-dimethylvinyl)-2,2-dimethylcyclopropane-2-carboxylicacid

A² --H: 3-(2',2'-dichlorovinyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A³ --H:3-(2'-chloro-3',3',3'-trifluoroprop-1-enyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A⁴ --H: 3-(2',2'-dibromovinyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A⁵ --H: 3-(2',2'-difluorovinyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A⁶ --H:3-(2'-fluoro-3',3',3'-trifluoroprop-1'-enyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A⁷ --H:3-(2',2'-bistrifluoromethylvinyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A⁸ --H: 2-(4'-chlorophenyl)-3-methylbutyric acid

A⁹ --H: 2-(4'-fluorophenyl)-3-methylbutyric acid

A¹⁰ --H: 2-(4'-difluoromethoxyphenyl)-3-methylbutyric acid

A¹¹ --H: 3-(4'-tert-butylphenyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A¹² --H: 2,2,3,3-tetramethylcyclopropane-1-carboxylic acid

A¹³ --H: 1-(4'-chlorophenyl)-cyclopropane-1-carboxylic acid

A¹⁴ --H: 1-(4'-ethoxyphenyl)-2,2-dichlorocyclopropane-1-carboxylic acid

A¹⁵ --H: 3-[2'-(4H₂-chlorophenyl)-2'-chlorovinyl]-2,2-dimethylcyclopropane-1-carboxylicacid

A¹⁶ --H: 3-(1',3'-butadienyl)-2,2-dimethylcyclopropane-1-carboxylic acid

A¹⁷ --H:3-(2'-methyl-2'-methoxycarbonylvinyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A¹⁸ --H: 2-(2'-chloro-4'-trifluoromethylphenylamino)-3-methylbutyricacid

A¹⁹ --H: 2-(2'-fluoro-4'-trifluoromethylphenylamino)-3-methylbutyricacid

A²⁰ --H: 3-methyl-2-(4'-trifluoromethylphenylamino)-butyric acid

A²¹ --H: 2-methyl-2-(pyrrol-1'-yl)-butyric acid

A²² --H: 3-methyl-2-(3'-methylpyrrol-1'-yl)-butyric acid

A²³ --H: 2-(3',4'-dimethylpyrrol-1'-yl)-methylbutyric acid

A²⁴ --H: 2-(2',5'-dimethylpyrrol-1'-yl)-methylbutyric acid

A²⁵ --H: 2-(isoindoline-2-yl)-3-methylbutyric acid

A²⁶ --H: 1,1-dimethyl-2,2[H]indenespirocyclopropane-3-carboxylic acid

A²⁷ --H: 3-cyclopentylidenemethyl-2,2-dimethylcyclopropane-1-carboxylicacid

A²⁸ --H:3-(1',2'-dibromo-2',2'-dichloroethyl)-2,2-dimethylcyclopropane-1-carboxylicacid

A²⁹ --H: 3-methyl-2-(pyrazol-1'-yl)-butyric acid

A³⁰ --H: 3-methyl-2-(imidazol-1'-yl)-butyric acid

The reaction can be accelerated in a conventional manner by adding acatalyst, such as sulfuric acid, a hydrogen halide, a sulfonic acid oran acidic ion exchanger and the equilibrium of the esterification can beshifted in the desired direction by removing the water or the ester IVfrom the reaction mixture, for example by azeotropic distillation or bybinding the water to sulfuric acid or a hydrohalic acid.

The corresponding acyl chlorides can also be reacted with the alcoholsof the formula Ia in the presence of an acid acceptor (cf. Houben-Weyl,Methoden der organischen Chemie, Volume VIII, page 541 et seq.,Georg-Thieme-Verlag, Stuttgart 1952).

Suitable acid acceptors are the conventional basic agents, in particularaliphatic, aromatic and heterocyclic amines, e.g. triethylamine,dimethylamine, piperidine, dimethylaniline, dimethylbenzylamine,pyridine and 2-picoline.

The reaction can be carried out in a solvent or diluent. The stated acidacceptors themselves or, for example, the following solvents or diluentsor mixtures thereof are suitable for this purpose:

Aliphatic and aromatic hydrocarbons and chlorohydrocarbons, such aspetroleum ether, benzene, toluene, xylene, gasoline, dichloromethane,chloroform, tetrachloromethane, 1,2-dichloroethane or chlorobenzene;ethers, such as diethyl and di-n-butyl ether, methyl tert-butyl ether,tetrahydrofuran and dioxane; ketones, for example acetone, methyl ethylketone and methyl isopropyl ketone; and nitriles, such as acetonitrileand propionitrile.

The starting materials are usually produced in a stoichiometric ratio.However, an excess of one or other of the starting materials may bequite advantageous in specific cases.

The reaction usually takes place at a sufficient rate at above 0° C.Since it is generally exothermic, it may be advantageous to provide ameans of cooling.

In some cases, it is useful and advantageous to esterify the compoundsof the formula Ia in situ, particularly when R³ in the general formulaIa is a cyano group.

The novel esters may furthermore be prepared by virtually any knownmethod of ester synthesis, for example by reacting the correspondinganhydride with an alcohol of the formula Ia, reacting the correspondingsalt with a derivative of an alcohol of the formula Ia or bytransesterification (cf. Houben-Weyl, loc. cit., pages 508-628).

In the present invention, the terms have the following meanings, unlessstated otherwise:

Alkyl is straight-chain or branched alkyl of 1 to 20, in particular 1 to12, carbon atoms. Examples are methyl, ethyl, propyl, isopropyl,n-butyl, isobutyl, sec-butyl and tert-butyl.

Alkenyl is a straight-chain or branched, ethylenically unsaturatedhydrocarbon group having 2 to 20, in particular 2 to 12, carbon atomsand 1 to 10, in particular 1 to 5, ethylenic bonds. Examples are vinyl,isopropenyl, 1-butenyl, 1,5-hexadienyl, 1-methylpropenyl and1-ethylvinyl.

Cycloalkyl is a cycloalkyl group having 3 to 8, in particular 3 to 6,carbon atoms in the ring, such as cyclopropyl, cyclobutyl, cyclopentylor cyclohexyl. This cycloalkyl group is unsubstituted or substituted byone or more, for example 1 to 4, branched or straight-chain C₁ -C₅-alkyl radicals, such as methyl, ethyl, propyl, isopropyl, butyl,sec-butyl, tert-butyl or pentyl. Examples are 3,5-diethylcyclohexyl andtetramethylcyclopropyl.

Cycloalkenyl is a cycloalkenyl group having 3 to 8, in particular 3 to6, carbon atoms in the ring, such as cyclopropenyl, cyclobutenyl,cyclopentenyl, cyclopentadienyl or cyclohexadienyl. This cycloalkenylgroup is unsubstituted or substituted by one or more, for example 1 to4, branched or straight-chain C₁ -C₅ -alkyl radicals, such as methyl,ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl or pentyl.Examples are 1-cyclopentenyl, 1-cyclohexenyl,3,5-dimethyl-1-cyclohexenyl and 1,3-cyclohexadienyl.

Bicycloalkyl is a bicycloalkyl radical having 5 to 12, in particular 6to 8, carbon atoms in the bicyclic structure, e.g. 2-norbornyl orbicyclo[4.1.0]hept-1-yl. This bicyclic structure is unsubstituted orsubstituted by one or more, for example 1 or 2, branched orstraight-chain alkyl radicals, such as methyl, ethyl, propyl, isopropyl,butyl, sec-butyl or pentyl. An example is2,6-dimethylbicyclo[4.1.0]hept-1-yl.

Bicycloalkenyl is an unsaturated bicycloalkyl group having 5 to 12, inparticular 6 to 8, carbon atoms in the bicyclic structure and one ormore, for example 1 or 2, ethylenic double bonds, e.g. norbornen-2-yl ornorbornadien-2-yl. This bicycloalkenyl group is unsubstituted orsubstituted by one or more, for example 1 to 3, branched orstraight-chain C₁ -C₅ -alkyl radicals, such as methyl, ethyl, propyl,isopropyl, butyl, sec-butyl or pentyl. An example is7,7-dimethylbicyclo[4.1.0]hept-2-en-1-yl.

R³ is hydrogen, cyano, C₂ -C₄ -alkynyl, such as ethynyl, propyn-1-yl,propyn-2-yl or butynyl C₂ -C₄ -alkenyl, such as vinyl, allyl or butenyl,or C₁ -C₄ -alkyl, such as methyl, ethyl, propyl, isopropyl or butyl.

In the compounds I, R¹ is preferably methyl, R² is preferably a branchedalkyl or alkenyl radical of 3 to 8 carbon atoms, such as isopropyl,isopropenyl, sec-butyl, 1-buten-2-yl, 1-methyl-1-propenyl,1,3-butadienyl, isopentyl, sec-pentyl, 3-penten-3-yl, 1-penten-2-yl orsec-hexyl, the three first-mentioned radicals being particularlypreferred, C₃ -C₈ -cycloalkyl or cycloalkenyl, such as cyclopentyl,1-cyclopentenyl, cyclohexyl, 1-cyclohexenyl or cyclopropenyl, or C₆ -C₈-bicycloalkyl or bicycloalkenyl, such as 2-norbornyl, 2-norbornen-2-ylor 2,5-norbornadien-2-yl, R³ is hydrogen, ethynyl or cyano and X ishydrogen or fluorine.

The novel compounds are prepared by the following processes:

Benzyl alcohols of the general formula Ia ##STR11## are obtainedstarting from a correspondingly substituted benzaldehyde of the formulaIb ##STR12## by reacting it with: i) a reducing agent if R³ is H,

ii) hydrocyanic acid or a metal cyanide in the presence or absence of anacid if R³ is CN or

iii) a metalorganyl MeR³ or R³ MeHal if R³ is C₂ -C₄ -alkynyl, C₂ -C₄-alkenyl or C₁ -C₄ -alkyl, Me being an alkali metal, alkaline earthmetal or transition metal and Hal being halogen.

Suitable reducing agents are all conventional reducing agents whichconvert benzaldehydes into benzyl alcohols (Houben-Weyl, Methoden derorganischem Chemie, Volume VI/1b, pages 1-500, 1984 Edition, GeorgThieme Verlag, Stuttgart). In addition to the catalytic hydrogenation,nonmetallic reducing agents and metal hydrides, in particular complexmetal hydrides, e.g. lithium aluminum hydride or sodium borohydride aresuitable. Cathodic and photochemical reduction are also suitable.

For the preparation of the cyanohydrins, the benzaldehydes are reactedwith hydrocyanic acid, with hydrocyanic acid produced in situ from metalcyanides, or with metal cyanides in the presence of an alkali metalbisulfite solution, if necessary basic catalysts, such as potassiumcarbonate, or phase transfer catalysts, e.g. benzyltriethylammoniumchloride, being added.

Preferably used metal cyanides are alkali metal cyanides, e.g. sodiumcyanide or potassium cyanide.

The reaction is carried out in a conventional manner, for example asdescribed in Houben-Weyl, Methoden der organischen Chemie, Volume VIII,pages 274-278, 1952 Edition, and Volume E5, page 1413 et seq., 1985Edition.

Suitable metalorganyls are the corresponding organometallic compounds,in particular lithiumorganyl compounds LiR³, such as methyllithium,ethyllithium or butyllithium or the corresponding Grignard compounds R³MgHal, where Hal is chlorine, bromine or iodine, e.g. methylmagnesiumbromide, ethylmagnesium chloride, propylmagnesium iodide orvinylmagnesium iodide.

The reaction of the metalorganyls can be carried out in a conventionalmanner, for example as described in Houben-Weyl, Methoden derorganischen Chemie, Volume 13/2a, page 285 et seq., 1973, in an inertorganic solvent such as ether or tetrahydrofuran, under a protectivegas, so that no further information is required in this context.

The benzaldehydes Ib are prepared by reacting a correspondinglysubstituted benzonitrile Ic ##STR13## with a reducing agent to give analdimine II ##STR14## and hydrolyzing this in a conventional manner.

This reaction sequence is shown in the following equation: ##STR15##

In addition to hydrogen (catalytic hydrogenation) reducing agents arealuminum hydrides, e.g. diisopropylaluminum hydride (cf. Houben-Weyl,Methoden der organischen Chemie, Volume E3, pages 476-488, Georg ThiemeVerlag, Stuttgart). The hydrolysis of the aldimines II is carried out asa rule by treatment with a dilute or concentrated mineral acid, such ashydrochloric acid. In the case of sensitive aldehydes, it is advisableto use buffered acetic acid.

It is not absolutely essential to isolate the aldimines II. They canadvantageously be hydrolyzed immediately to the benzaldehydes Ib,without working up and purification.

The benzonitriles of the general formula Ic are prepared by reacting##STR16## compounds of the general formula III ##STR17## where Y ischlorine or bromine, with metal cyanides in an organic solvent inaccordance with the following equation. ##STR18##

Suitable metal cyanides (MeCN) are alkali metal, alkaline earth metaland heavy metal cyanides (Houben-Weyl, Methoden der organischen Chemie,Volume E5, pages 1447-1467, 1985 Edition, Georg Thieme Verlag,Stuttgart). The use of copper(I) cyanide is particularly advantageous.The reaction takes place smoothly in aprotic, polar solvents.Dimethylformamide, pyridine, 1-methyl-2-pyrrolidone and phosphoric acidtris-(dimethylamide) are particularly suitable.

The reaction is advantageously carried out at from 100° to 250° C. Whencopper(I) cyanide is used, the reaction mixture is worked up(destruction of the initially formed nitrile/copper halide/coppercyanide complex) with iron(III) chloride/hydrochloric acid,1,2-diaminoethane or sodium cyanide. 1,2-Diaminoethane is advantageouslyused.

Specific examples of the compounds III, such as2-chloro-6-n-butyltoluene, 3-chloro-2-methylstyrene,1-chloro-2-methyl-3-(1'-propenyl)-benzene, 2,3-dimethylchlorobenzene,2,3-dimethylbromobenzene, 4-fluoro-2,3-dimethylbromobenzene,1,2-dichloro-3,4-dimethylbenzene, 1,5-dichloro-2,3-dimethylbenzene and1,4-dichloro-2,3-dimethylbenzene are disclosed in U.S. Pat. No.4,538,003; European Patent 80 359; J. Med. Chem. 28 (10), 1436-1440; J.Chromatogr. 370 (3) (1986), 355-376; Gazz. Chim. Hal., 103 (8-9) (1973),1019-1025 or Chem.-Ztg. 103 (1) (1979), 1-7.

A general synthesis route for the preparation of the compounds of theformula III where R¹, R², X and Y have the abovementioned meaningsstarts from dichloro-, dibromo-, dibromochloro-, dibromofluoro- ordichlorofluorobenzene derivatives Va and is illustrated by the followingreaction scheme: ##STR19##

In this reaction scheme, the side chains ##STR20## correspond to theradical R². R⁴, R⁵ and R⁶ are each hydrogen, branched or straight-chainalkyl or branched or straight-chain alkenyl. R⁴ and R⁶ or R⁵ and R⁶ mayfurthermore be bonded to form a ring, which may be substituted by C₁ -C₅-alkyl, or R⁴, R⁵ and R⁶ are such that they form a bicyclic ketone,which may be substituted by C₁ -C₅ -alkyl.

Di- or trihalobenzenes of the general formula Va, where R¹ is methyl orethyl, X is hydrogen, chlorine or fluorine and Y is chlorine or bromine,are converted into the monometalorganyls of the general formula Vb(organolithium compound or Grignard compound), where X, Y and R¹ havethe meaning stated for Va and M is lithium or MgY.

The conventional preparation processes which start from aryl halides(cf. Houben-Weyl, Methoden der organischen Chemie, Volume XIII/1, page134 et seq., 1970 Edition, and Volume XIII/2a, page 54 et seq., 1973Edition, Georg Thieme Verlag, Stuttgart) are suitable for thepreparation of organolithium or Grignard compounds. Where Y is chlorineand X is hydrogen, the synthesis of the Grignard compounds requireshigher reaction temperatures. The use of tetrahydrofuran at boilingpoint has proven particularly useful.

The organometallic compounds Vb are reacted with carbonyl compounds VI,in which R⁴ to R⁶ have the above-mentioned meanings, to give benzylalcohols VII. These are dehydrated to styrenes of the general formulaIII', the methods described in Houben-Weyl (Methoden der organischenChemie, Volume V/Ib, page 45 et seq., 1972 Edition, Georg-Thieme-Verlag,Stuttgart) being suitable. It is advantageous to use acidic dehydratingagents, in particular oxalic acid or p-toluenesulfonic acid, withsimultaneous removal of the resulting water by means of a separator.

The styrene derivatives III' prepared in the manner described above areeither used directly for the preparation of the benzonitriles of thegeneral formula Ic or first converted into compounds of the generalformula III" by reduction. This may be effected both by noncatalyticreduction (for example with ethanol and sodium) and by catalytichydrogenation (cf. Houben-Weyl, Methoden der organischen Chemie, VolumeV/la, page 405 et seq., 1970 Edition, Georg Thieme Verlag, Stuttgart).Examples of suitable catalysts are PtO₂, Raney nickel, Pd/carbon,Pd/CaCO₃, copper chromite or Pd/Al₂ O₃. The use of Pd/carbon has provenparticularly useful. Suitable solvents are alcohols, e.g. methanol,ethanol or isopropanol, ethers, e.g. tetrahydrofuran or dioxane, andesters, e.g. ethyl acetate. It is advantageous to use ethanol. Thecatalytic hydrogenation is carried out, as a rule, at room temperatureand under from 1 to 150 bar. Small amounts of compounds in whichhalogen/hydrogen exchange has additionally taken place are often formedas byproducts.

Compounds of the general formula III ##STR21## where R² is a tertiaryalkyl radical or tertiary alkenyl radical, can be prepared starting fromcompounds of the general formula Va.

The following reaction scheme is intended as an example of the synthesisroute: ##STR22##

Compounds of the general formula I ##STR23## where R² is unsubstitutedor substituted cyclopropyl, can be obtained by various methods:

a) By the process described below, in which the required startingmaterials XV can be obtained by an addition reaction of a dihalocarbenewith compounds of the general formula III' followed by dehalogenation(for example with tri-n-butyltin hydride). ##STR24## (R⁴, R⁵ and R⁶ areeach H or C₁ -C₅ -alkyl)

Dihalocarbene addition and subsequent dehalogenation are carried out ina subsequent stage (correspondingly substituted benzonitriles,benzaldehydes or benzyl alcohols), where Z, X, R¹ and R⁴ -R⁶ have theabovementioned meanings: ##STR25## where Z is --CHO or ##STR26## it isadvantageous to introduce protective groups for these functional groupsbeforehand (for example acetal or tetrahydropyranyl ether) and toeliminate these in a conventional manner after the dehalogenation.

The novel compounds or their intermediates are prepared in accordancewith the descriptions of the following examples or by appropriatemodification of these examples.

EXAMPLE 1 Preparation of benzyl alcohols VII1-(3'-Chloro-2'-methylphenyl)-cyclohexanol

96 g (4 moles) of Mg turnings in 60 ml of absolute tetrahydrofuran (THF)are initially taken under a nitrogen atmosphere. 1 ml of1,2-dibromoethane is added at 65° C., after which a solution of 644 g (4moles) of 2,6-dichlorotoluene in 1.5 l of absolute THF is added dropwisein the course of 21/4 hours. Thereafter, the mixture is stirred for 4hours under reflux and cooled to room temperature, and 352.8 g (3.6moles) of cyclohexanone in 250 ml of absolute THF are added undernitrogen. When the reaction is complete, the Grignard reaction mixtureis worked up in an aqueous medium in a conventional manner and thesolvent is substantially removed by distillation under reduced pressure.The residue is subjected to incipient distillation (30°-107° C./0.27mbar). The remaining crude product (676 g), which contains as much as90% of 1-(3-chloro-2'-methylphenyl)-cyclohexanol, can be furtherpurified by column chromatography using toluene as the mobile phase.

300 MHz NMR spectrum in CDCl₃ :

δ [ppm]=1.58-2.0(1OH); 2.65(3H); 7.04(1H); 7.23-7.34(2H).

For example, the following alcohols, which are characterized by thephysical data stated, are prepared by the process described above:

    ______________________________________                                         ##STR27##       mp.: 55-59° C.                                         ##STR28##       300 MHz NMR spectrum in CDCl.sub.3 : δ [ppm] =                          0.82(3H); 1.62(3H); 1.86-2.07[2H + 1H(OH)]; 2.59(3H);                         7.06(1H); 7.29(1H); 7.36(1H)                                  ##STR29##       300 MHz NMR spectrum in CDCl.sub.3 : δ [ppm] =                          0.84(3H); 0.96(3H); 1.83-1.96(1H); 2.19(1H); 2.32(3H);                        4.63(1H); 7.1(1H); 7.23-7.33(2H)                              ##STR30##       mp.: 113° C.                                           ##STR31##       mp.: 90-93° C.                                         ##STR32##       mp.: 52- 55° C.                                       ______________________________________                                    

EXAMPLES 2 TO 31 Preparation of halobenzene derivatives III2-Methyl-3-isopropenylchlorobenzene

190 g of 3-chloro-2-methyl-alpha,alpha-dimethylbenzyl alcohol arerefluxed with 1.5 l of toluene and 370 g of oxalic acid under a waterseparator until no more water separates off. The oxalic acid is filteredoff under suction and the filtrate is washed with sodium bicarbonatesolution, dried over sodium sulfate and evaporated down. Fractionaldistillation of the residue gives 91.5 g of the desired compound, whichis listed in Table 1 as Example 2.

300 MHz NMR spectrum in CDCl₃ :

δ][ppm]=1.98(3H); 2.32(3H); 4.82(1H); 5.17(1H); 6.95-7.07(2H); 7.23(1H).

3-Cyclohexyl-2-methylchlorobenzene

103 g of 1-(3'-chloro-2'-methylphenyl)-cyclohexene are dissolved in1,200 ml of ethanol, and 5 g of Pd/carbon are added. Hydrogenation iscarried out for 8 hours at room temperature and under a hydrogenpressure of 80 bar. The catalyst is filtered off from the reactionmixture and the solution is evaporated down. Fractional distillationgives 51.8 g of 3-cyclohexyl-2-methylchlorobenzene (Example 3 in Table1).

300 MHz NMR spectrum in CDCl₃ :

δ [ppm]=1.2-1.49(5H); 1.7-1.92(5H); 2.36(3H); 2.72(1H); 7.01-7.2(3H).

The compounds stated in Table 1 below were prepared similarly to Example2 or 3 described above and are characterized by the physical datastated; the other compounds in Table 1 can readily be obtained usingcorresponding starting materials.

                                      TABLE 1                                     __________________________________________________________________________    Halobenzene derivatives of the formula III                                     ##STR33##                            III                                     Example                                                                            Y R.sup.1                                                                          R.sup.2      X  Physical Data                                       __________________________________________________________________________     2   Cl                                                                              CH.sub.3                                                                         Isopropenyl  H  bp. 54-55° C./0.13 mbar                       3   Cl                                                                              CH.sub.3                                                                         Cyclohexyl   H  bp. 88-93° C./0.013 bar                       4   Cl                                                                              CH.sub.3                                                                         n-Propyl     H                                                       5   Cl                                                                              CH.sub.3                                                                          ##STR34##   H                                                       6   Br                                                                              CH.sub.3                                                                         Cyclopentyl  H                                                       7   Cl                                                                              CH.sub.3                                                                         1-Cyclohexenyl                                                                             H  bp. 95-98° C./0.2 mbar                                                 n.sub.D.sup.23 = 1.5501                              8   Br                                                                              C.sub.2 H.sub.5                                                                  Isopropyl    H                                                       9   Cl                                                                              CH.sub.3                                                                         Cyclohexyl   5-F                                                    10   Cl                                                                              CH.sub.3                                                                         Isopropyl    5-Cl                                                   11   Cl                                                                              CH.sub.3                                                                         Isopropyl    H  bp. 55° C./0.27 mbar                         12   Br                                                                              CH.sub.3                                                                         Isopropyl    H                                                      13   Cl                                                                              C.sub.2 H.sub.5                                                                  Isopropenyl  H                                                      14   Br                                                                              CH.sub.3                                                                         Isopropenyl  H                                                      15   Cl                                                                              CH.sub.3                                                                         sec-Butyl    H  bp. 58-60° C./0.13 mbar                      16   Cl                                                                              CH.sub.3                                                                          ##STR35##   H                                                      17   Cl                                                                              CH.sub.3                                                                         1-Cyclopentenyl                                                                            H                                                      18   Cl                                                                              CH.sub.3                                                                         2,5-Norbornadien-2-yl                                                                      H                                                      19   Cl                                                                              CH.sub.3                                                                         2-Norbornen-2-yl                                                                           H  bp. 113° C./0.06 mbar                                                  n.sub.D.sup.21 = 1.5702                             20   Cl                                                                              CH.sub.3                                                                         2-Norbornen-2-yl                                                                           5-F                                                    21   Br                                                                              CH.sub.3                                                                         2-Norbornen-2-yl                                                                           H                                                      22   Cl                                                                              C.sub.2 H.sub.5                                                                  Norborn-2-yl H                                                      23   Cl                                                                              CH.sub.3                                                                         Norborn-2-yl H  bp. 109-110° C./0.013 mbar                   24   Cl                                                                              CH.sub.3                                                                         3,5-Diethylcyclohexyl                                                                      H                                                      25   Cl                                                                              CH.sub.3                                                                         1,3-Cyclohexadienyl                                                                        H                                                      26   Br                                                                              CH.sub.3                                                                          ##STR36##                                                          27   Cl                                                                              CH.sub.3                                                                          ##STR37##   H  bp. 70-72° C./0.013 mbar                     28   Cl                                                                              C.sub.2 H.sub.5                                                                   ##STR38##   H                                                      29   Cl                                                                              CH.sub.3                                                                          ##STR39##   H                                                      30   Cl                                                                              CH.sub.3                                                                          ##STR40##   H                                                      31   Cl                                                                              CH.sub.3                                                                         CH(C.sub.2 H.sub.5).sub.2                                                                  H  bp. 60-62° C./0.013 mbar                     __________________________________________________________________________

EXAMPLES 32 TO 65 AND 131 Preparation of benzonitriles Ic3-(1'-cyclohexenyl)-2-methylbenzonitrile

250 g (0.6 mole) of 1-(3'-chloro-2'-methylphenyl)cyclohexene, 600 ml of1-methyl-2-pyrrolidone and 63 g of anhydrous copper(I) cyanide areheated to the boil for 35 hours while stirring. The reaction mixture ispoured into a solution of 500 ml of ethylenediamine in 1.5 l of waterand the mixture is stirred for 45 minutes at 50° C. and extractedseveral times with toluene. The combined organic phases are extracted byshaking with 10% strength sodium cyanide solution, dried over Na₂ SO₄and evaporated down. Purification by column chromatography over silicagel using 3:7 toluene/cyclohexane as the eluent gives 117.8 g of thenitrile of melting point 54°-57° C.

250 MHz NMR spectrum in CDCl₃ :

δ [ppm]=1.72(4H); 2.13(4H); 2.46(3H); 5.55(1H); 7.17-7.31(2H); 7.49(1H).

The novel benzonitriles stated in Table 2 were prepared by the processdescribed above and are characterized by the physical properties stated;the other compounds in Table 2 can readily be obtained usingcorresponding starting materials.

                                      TABLE 2                                     __________________________________________________________________________    Benzonitriles of the formula Ic                                                ##STR41##                                   Ic                               Example                                                                            R.sup.1                                                                          R.sup.2      X  Physical Properties                                   __________________________________________________________________________    32   CH.sub.3                                                                         1-Cyclohexenyl                                                                             H  mp.: 54 to 57° C.                              33   CH.sub.3                                                                         n-Propyl     H                                                        34   CH.sub.3                                                                         n-Butyl      H                                                        35   CH.sub.3                                                                         CH(C.sub.2 H.sub.5).sub.2                                                                  H  n.sub.D.sup.23 : 1.5119                               36   C.sub.2 H.sub.5                                                                  Isopropyl    H                                                        37   CH.sub.3                                                                         Isopropyl    H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.23(6H); 2.55(3H); 3.19(1H);                                 7.25(1H); 7.46(2H)                                    38   CH.sub.3                                                                         Isopropyl    6-F                                                      39   CH.sub.3                                                                          ##STR42##   H                                                        40   C.sub.2 H.sub.5                                                                  Isopropenyl  H                                                        41   CH.sub.3                                                                          ##STR43##   H                                                        42   CH.sub.3                                                                         Isopropenyl  H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 2.02(3H); 2.52(3H); 4.89(1H);                                 5.3(1H); 7.22-7.4(2H); 7.56(1H)                       43   CH.sub.3                                                                         Isopropenyl  5-Cl                                                     44   CH.sub.3                                                                          ##STR44##   H                                                        45   CH.sub.3                                                                          ##STR45##   H                                                        46   CH.sub.3                                                                          ##STR46##   H                                                        47   CH.sub.3                                                                         sec. Butyl   H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 0.84(3H); 1.2(3H); 1.61(2H);                                  2.54(3H);                                                                     2.94(1H); 7.2-7.31(1H); 7.43(2H)                      48   C.sub.2 H.sub.5                                                                  sec. Butyl   H                                                        49   CH.sub.3                                                                          ##STR47##   H                                                        50   C.sub.2 H.sub.5                                                                  CH(C.sub.2 H.sub.5).sub.2                                                                  H                                                        51   CH.sub.3                                                                         Cyclopentyl  H                                                        52   CH.sub.3                                                                         Cyclohexyl   H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.2-1.5(5H); 1.71-1.93(5H);                                   2.55(3H);                                                                     2.75(1H); 7.23(1H); 7.42(2H)                          53   CH.sub.3                                                                         Cyclopropyl  H                                                        54   CH.sub.3                                                                         1-Cyclopentenyl                                                                            H                                                        55   CH.sub.3                                                                         1,3-Cyclohexadienyl                                                                        H                                                        56   CH.sub.3                                                                         2-Norbornen-2-yl                                                                           H                                                        57   CH.sub.3                                                                         Norborn-2-yl H  mp. 74 to 76° C.                               58   C.sub.2 H.sub.5                                                                  Cyclohexyl   H                                                        59   CH.sub.3                                                                         2,5-Norbornadien-2-yl                                                                      H                                                        60   CH.sub.3                                                                         Cycloheptyl  H                                                        61   CH.sub.3                                                                          ##STR48##   H                                                        62   CH.sub.3                                                                          ##STR49##   H  n.sub.D.sup.22 : 1.5254                               63   CH.sub.3                                                                          ##STR50##   5-F                                                      64   C.sub.2 H.sub.5                                                                   ##STR51##   H                                                        65   CH.sub.3                                                                         CH(i-C.sub.3 H.sub.7).sub.2                                                                H                                                        131  CH.sub.3                                                                          ##STR52##   H  300-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] = 0.65(3H); 1.41(6H); 1.83(2H); 2.72(3H);                               7.2(1H); 7.5(2H)                                      __________________________________________________________________________

EXAMPLES 66 TO 94 AND 132 Preparation of the benzaldehydes Ib3-(1'-cyclohexenyl)-2-methylbenzaldehyde

460 ml (0.69 mole) of diisobutylaluminum hydride solution (25% strengthsolution in toluene) are carefully added dropwise at 20°-30° C. to asolution of 113 g (0.574 mole) of3-(1'-cyclohexenyl)-2-methylbenzonitrile in 1,000 ml of dry tolueneunder nitrogen. The mixture is stirred for a further 4 hours at roomtemperature and excess diisobutylaluminum hydride is decomposed with 120ml of methanol. 1,000 ml of 10% strength hydrochloric acid are added,after which stirring is continued overnight at room temperature. Theorganic phase is separated off and the aqueous phase is extractedseveral times with toluene. The combined organic phases are washed withwater and then dried over Na₂ SO₄. Removal of the solvent gives 109 g ofthe aldehyde (n_(D) ²² : 1.5621).

300 MHz NMR spectrum in CDCl₃ :

δ [ppm]=1.63-1.82(4H); 2.14(4H); 2.59(3H); 2.55(1H); 7.28(2H); 7.67(1H);10.29(1H).

The novel benzaldehydes stated in Table 3 below were prepared by theprocess described above and are characterized by the physical propertiesstated; the other compounds in Table 3 can readily be obtained usingcorresponding starting materials.

                                      TABLE 3                                     __________________________________________________________________________    Benzaldehydes                                                                  ##STR53##                                   Ib                               Example                                                                            R.sup.1                                                                          R.sup.2      X  Physical Properties                                   __________________________________________________________________________     66  CH.sub.3                                                                         1-Cyclohexenyl                                                                             H  n.sub.D.sup.22 = 1.5621                                67  CH.sub.3                                                                         Cyclopentyl  H                                                         68  CH.sub.3                                                                         1-Cyclopentenyl                                                                            H                                                         69  C.sub.2 H.sub.5                                                                  Cycloheptyl  H                                                         70  CH.sub.3                                                                         Cyclopropyl  H                                                         71  CH.sub.3                                                                         Cyclohexyl   5-Cl                                                      72  CH.sub.3                                                                         Cyclohexyl   H  mp. 42-45° C.                                   73  CH.sub.3                                                                         Norbornen-2-yl                                                                             H                                                         74  CH.sub.3                                                                         2,5-Norbornadien-2-yl                                                                      H                                                         75  CH.sub.3                                                                          ##STR54##   H                                                         76  CH.sub.3                                                                          ##STR55##   H                                                         77  CH.sub.3                                                                         CH(C.sub.2 H.sub.5).sub.2                                                                  H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 0.77(6H); 1.56(2H); 1.72(2H);                                 2.64(3H); 2.91(1H); 7.37(2H); 7.63(1H);                                       10.33(1H)                                              78  CH.sub.3                                                                          ##STR56##   H  250-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] = 0.86(3H); 1.22(3H); 1.62(2H); 2.64(3H);                               3.04(1H); 7.33(1H); 7.44(1H); 7.63(1H);                                       10.35(1H)                                              79  C.sub.2 H.sub.5                                                                   ##STR57##   H                                                         80 cis/trans                                                                      CH.sub.3                                                                          ##STR58##   H  200-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] = 0.89 and 0.97(3H); 1.36 and 1.8(3H); 2.25                             and 2.37(2H); 2.52 and 2.57(3H); 5.33 and                                     5.64(1H); 7.22-7.4(2H); 7.73(1H)                       81  CH.sub.3                                                                          ##STR59##   H                                                         82  CH.sub.3                                                                          ##STR60##   H                                                         83  CH.sub.3                                                                          ##STR61##   H                                                         84  CH.sub.3                                                                         Isopropyl    H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ  [ppm] = 1.27(6H); 2.66(3H); 3.3(1H);                                 7.33(1H); 7.5(1H); 7.65(1H); 10.32(1H)                 85  CH.sub.3                                                                         Isopropyl    5-F                                                       86  CH.sub.3                                                                         n-Propyl     H                                                         87  CH.sub.3                                                                         n-Butyl      H                                                         88  CH.sub.3                                                                          ##STR62##   H                                                         89  C.sub.2 H.sub.5                                                                  Isopropenyl  H                                                         90  CH.sub.3                                                                         Isopropenyl  H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 2.01(3H); 2.6(3H); 4.85(1H);                                  5.26(1H);                                                                     7.35(2H); 7.73(1H); 10.33(1H)                          91  CH.sub.3                                                                         1,3-Cyclohexadienyl                                                                        H                                                         92  CH.sub.3                                                                         Vinyl        H                                                         93  CH.sub.3                                                                          ##STR63##   H                                                         94  CH.sub.3                                                                         Norborn-2-yl H  200 MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.17-174(7H); 1.96(1H);                                       2.39(2H);                                                                     2.68(3H); 3.53(1H); 7.37(1H);                                                 7.52(1H); 7.69(1H); 10.38(1H)                         132  CH.sub.3                                                                          ##STR64##   H  300-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] =  0.68(3H); 1.42(6H); 1.86(2H); 2.8(3H);                               7.27(1H); 7.57(1H) 7.66(1H); 10.38(1H)                __________________________________________________________________________

EXAMPLES 95 TO 130 Preparation of the benzyl alcohols Ia3-(1'-cyclohexenyl)-2-methylbenzyl alcohol

A solution of 24 g (0.12 mole) of3-(1'-cyclohexenyl)-2-methylbenzaldehyde in 120 ml of ethanol is addeddropwise to a suspension of 2.3 g (0.06 mole) of sodium borohydride in120 ml of ethanol at room temperature. The mixture is stirred for 15hours at room temperature, after which 320 ml of 5% strengthhydrochloric acid are carefully added and extraction is carried outseveral times with ether. The combined ether phases are washed with 5%strength hydrochloric acid and then with water, dried and evaporateddown. 23 g of 3-(1'-cyclohexenyl)-2-methylbenzyl alcohol of meltingpoint 62°-64° C. (Example 95) are obtained.3-Sec-butyl-2-methyl-alpha-ethynylbenzyl alcohol

50 ml of THF (absolute) are saturated with acetylene at 0° C. and undera nitrogen atmosphere. 87 ml of methylmagnesium chloride solution (1.5molar) are added dropwise in the course of 45 minutes with furtherintroduction of acetylene, and the mixture is stirred for 30 minutes at0° C. At -20° C., a solution of 15.3 g of3-sec-butyl-2-methylbenzaldehyde in 20 ml of THF (absolute) is addeddropwise. Stirring is continued for 2 hours at -20° C., and the reactionmixture is allowed to stand overnight at room temperature and is pouredinto 300 ml of ice water. It is acidified with dilute hydrochloric acidand then extracted three times by shaking with ether. The combined etherextracts are washed with water, dried over sodium sulfate and evaporateddown to give 16.6 g of an oil (70% of desired compound) which, afterpurification by column chromatography over silica gel using toluene asthe mobile phase, gives 5.1 g of the pure benzyl alcohol (Example 96).

300 MHz NMR spectrum in CDCl₃ :

δ [ppm]=0.84 (3H); 1.17(3H); 1.57(2H); 2.36(3H); 2.57(1H); 2.62(1H);2.97(1H); 5.62(1H); 7.18(2H); 7.52(1H).

3-Cyclopropyl-2-methylbenzyl alcohol

a) Dihalocarbene addition: 10 ml of methylene chloride, 0.42 ml ofethanol, 0.14 g of benzyltriethylammonium chloride and 20.9 g (0.083mole) of bromoform are added to 9.9 g (0.042 mole) of2-methyl-3-vinylbenzyl tetrahydro-2-pyranyl ether. After the addition of13.28 g (0.166 mole) of ice-cold 50% strength NaOH, thorough stirring iscarried out for 1 hour at room temperature and for 8 hours at 50° C. Thereaction mixture is poured into 300 ml of water and is extracted threetimes with methylene chloride. The combined extracts are dried andevaporated down. Purification by column chromatography over silica gelusing toluene as the mobile phase gives 9.1 g of3-(2',2'-dibromocyclopropyl)-2-methylbenzyl tetrahydro-2-pyranyl ether.

250 MHz NMR spectrum in CDCl₃ :

δ [ppm]=1.45-1.95(6H); 2.02(1H); 2.15(1H); 2.46(3H); 2.84(1H); 3.55(1H);3.9(1H); 4.55(1H); 4.72(1H); 4.88(1H); 6.93(1H); 7.14(1H); 7.37(1H).

b) Dehalogenation: 45.2 g (0.155 mole) of tri-n-butyltin hydride areadded, at 0° C., to 29.7 g (0.074 mole) of the dibromocyclopropylcompound prepared under a) and 150 ml of n-hexane. The mixture isstirred for 1 hour at room temperature and for 10 hours under reflux. Itis refluxed for a further 20 hours, a total of 15 g of tri-n-butyltinhydride being added a little at a time. The cooled reaction solution isevaporated down. Purification by column chromatography over silica gelusing toluene as the mobile phase gives 17.1 g of3-cyclopropyl-2-methylbenzyl tetrahydro-2-pyranyl ether.

200 MHz NMR spectrum in CDCl₃ :

δ [ppm]=0.62(2H); 0.91(2H); 1.5-2.0(6H+1H); 1.94(3H); 3.6(1H); 3.97(1H);4.52(1H); 4.76(1H); 4.87(1H); 7.02.7.21(2H); 7.29(1H).

c) Elimination of the protective group: 16.7 g of3-cyclopropyl-2-methylbenzyl tetrahydro-2-pyranyl ether in 180 ml ofmethanol are stirred overnight at room temperature with 10.8 ml ofconcentrated hydrochloric acid. The mixture is neutralized with sodiummethylate solution while cooling with ice and is then evaporated down.Water is added to the residue, which is then extracted several timeswith ether. The combined ether extracts are washed with water, dried andevaporated down. The crude product (11.5 g) is purified by columnchromatography over silica gel using toluene as the mobile phase. 8.9 gof 3-cyclopropyl-2-methylbenzyl alcohol (Example 100) are obtained.

300 MHz NMR spectrum in CDCl₃ :

δ [ppm]0.61(2H); 0.93(2H); 1.88(1H); 2.15(1H); 2.43(3H); 4.63(2H);6.97-7.19(3H).

The novel benzyl alcohols stated in Table 4 below were prepared by theprocesses described in Preparation Examples 95, 96 and 100 and arecharacterized by the physical properties stated; the other compounds inTable 4 can readily be obtained using corresponding starting materials.

                                      TABLE 4                                     __________________________________________________________________________    Benzyl alcohols of the formula Ia                                              ##STR65##                                         Ia                         Example                                                                            R.sup.1                                                                          R.sup.2      R.sup.3                                                                            X  Physical properties                              __________________________________________________________________________     95  CH.sub.3                                                                         1-Cyclohexenyl                                                                             H    H  mp. 62 to 64° C.                           96  CH.sub.3                                                                         sec-Butyl    Ethynnyl                                                                           H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 0.84(3H); 1.17(3H);                                           1.57(2H); 2.36(3H);                                                           2.57(1H); 2.62(1H); 2.97(1H); 5.62(1H);                                       7.18(2H); 7.52(1H)                                97  CH.sub.3                                                                         Cyclopentyl  H    H                                                    98  CH.sub.3                                                                         1-Cyclopentenyl                                                                            H    H                                                    99  CH.sub.3                                                                         1-Cyclopentenyl                                                                            Ethynyl                                                                            H                                                   100  CH.sub.3                                                                         Cyclopropyl  H    H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 0.61(2H); 0.93(2H);                                           1.88(1H); 2.15(1H);                                                           2.4(3H); 4.63(2H); 6.97-7.19(3H)                 101  CH.sub.3                                                                         Cyclohexyl   H    5-Cl                                                102  CH.sub.3                                                                         Cyclohexyl   H    H  mp. 87-88° C.                             103  CH.sub. 3                                                                        Cyclohexyl   Ethyl                                                                              H                                                   104  CH.sub.3                                                                         2-Norbornen-2-yl                                                                           H    H                                                   105  CH.sub.3                                                                         2,5-Norborna-                                                                              H    H                                                           dien-2-yl                                                             106  CH.sub.3                                                                         Norborn-2-yl H    H  200 MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.21-1.73 [7H + 1H(OH)];                                      1.94(1H);                                                                     2.37(3H + 2H); 3.5(1H); 4.77(2H); 7.26(3H)       107  CH.sub.3                                                                         CH(C.sub.2 H.sub.5).sub.2                                                                  H    H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 0.79(6H); 1.49-1.8(4H);                                       1.7(1H);                                                                      2.34(3H); 2.85(1H); 4.74(2H); 7.21(3H);          108  CH.sub.3                                                                         Isopropyl    H    H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.22(6H); 2.24(1H);                                           2.31(3H); 3.22(1H);                                                           4.63(2H); 7.12-7.24(3H)                          109  CH.sub.3                                                                         Isopropyl    CH.sub.3                                                                           H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.22(6H); 1.43(3H);                                           2.27(3H); 2.45(1H);                                                           3.21(1H); 5.14(1H); 7.19(2H); 7.35(1H);          110  CH.sub.3                                                                         Isopropyl    H    5-Cl                                                111  CH.sub.3                                                                         Isopropyl    Ethynyl                                                                            H                                                   112  CH.sub.3                                                                          ##STR66##   H    H                                                   113  CH.sub.3                                                                         n-Propyl     H    H                                                   114  CH.sub.3                                                                         n-Butyl      H    H                                                   115  CH.sub.3                                                                         Isopropenyl  H    H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.83(1H); 2.0(3H); 2.28(3H);                                  4.71(2H);                                                                     4.82(1H); 5.2(1H); 7.05-7.33(3H)                 116  CH.sub.3                                                                         Isopropenyl  Ethynyl                                                                            H                                                   117  CH.sub.3                                                                         Isopropenyl  CN   H                                                   118  CH.sub.3                                                                         Isopropenyl  Vinyl                                                                              H  200-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 2.02(3H); 2.13(broad, 1H);                                    2.33(3H);                                                                     4.85(1H); 5.19-5.5(4H); 5.97-6.14(1H);                                        7.07(1H); 7.2(1H); 7.4(1H)                       119  CH.sub.3                                                                          ##STR67##   H    H                                                   120  CH.sub.3                                                                          ##STR68##   H    H                                                   121  CH.sub.3                                                                          ##STR69##   H    H  n.sub.D.sup.22 : 1.5325                          122  CH.sub.3                                                                          ##STR70##   H    H  200-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] = 0.88(3H); 1.22(3H); 1.64(2H);                                         1.86(1H); 2.33(3H); 3.0(1H); 4.72(2H);                                        7.22(3H)                                         123  CH.sub.3                                                                         CH(C.sub.2 H.sub.5).sub.2                                                                  Isopropyl                                                                          H                                                   124  C.sub.2 H.sub.5                                                                   ##STR71##   H    H                                                   125  CH.sub.3                                                                          ##STR72##   H    H                                                   126  CH.sub.3                                                                          ##STR73##   H    H                                                   127  CH.sub.3                                                                         3,5-Diethyl- H    H                                                           cyclohexyl                                                            128  CH.sub.3                                                                          ##STR74##   H    H                                                   129  CH.sub.3                                                                         vinyl        H    H  300-MHz-NMR-spectrum in CDCl.sub.3 :                                          δ [ppm] = 1.97(1H); 2.29(3H);                                           4.65(2H); 5.3(1H);                                                            5.58(1H); 6.93-7.04(1H); 7.11-7.28(2H);                                       7.4(1H)                                                                       Schmp: 38-43° C.                          130  CH.sub.3                                                                          ##STR75##   H    H  300-MHz-NMR-spectrum in CDCl.sub.3 : δ                                  [ppm] = 0.67(3H); 1.39(6H); 1.83(2H + 1H);                                    2.46(3H); 4.66(2H); 7.09-7.31(3H)                __________________________________________________________________________

We claim:
 1. A novel benzonitrile of formula I: ##STR76## wherein R¹ ismethyl or ethyl, and R² is a member selected from the group consistingof branched C₃₋₂₀ alkyl and branched C₃₋₂₀ alkenyl.
 2. A novelbenzonitrile of the formula I: ##STR77## wherein R¹ is methyl or ethyl,and R² is C₃₋₈ cycloalkyl, C₃₋₈ cycloalkenyl, C₅₋₁₂ bicycloalkyl, C₅₋₁₂bicycloalkenyl, C₁₋ C₅ -alkyl-substituted C₃₋₈ cycloalkyl, C₁ -₅-alkyl-substituted, C₃₋₈ cycloalkenyl, C₁₋₅ -alkyl-substituted, C₅₋₁₂bicycloalkyl C₁ -C₅ -alkyl-substituted and C₅₋₁₂ bicycloalkenyl.
 3. Thecompound of claim 1, wherein R¹ is methyl.
 4. The compound of claim 1,wherein R¹ is ethyl.
 5. The compound of claim 1, wherein R² is branchedC₃₋₂₀ alkyl.
 6. The compound of claim 1, wherein R² is branched C₃₋₂₀alkenyl.
 7. The compound of claim 2, wherein R² is C₃₋₈ cycloalkyl. 8.The compound of claim 2, wherein R² is C₃₋₈ cycloalkenyl.
 9. Thecompound of claim 1, wherein R² is C₅₋₁₂ bicycloalkyl.
 10. The compoundof claim 1, wherein R² is C₅₋₁₂ bicycloalkenyl.
 11. The compound ofclaim 1, wherein R² is C₁ -C₅ -alkyl-substituted C₅₋₁₂ cycloalkyl. 12.The compound of claim 1, wherein R² is C₁ -C₅ -alkyl-substituted C₅₋₁₂cycloalkenyl.
 13. The compound of claim 1, wherein R² is C₁ -C₅-alkyl-substituted C₅₋₁₂ bicycloalkyl.
 14. The compound of claim 1,wherein R² is C₁ -C₅ -alkyl-substituted C₅₋₁₂ bicycloalkenyl.